I think that during our spouse's MLC we have to focus on ourselves, and keeping our family going. We have no way really of knowing what will prolong either the affair, or the crisis itself. What is important is how we behave, grow and develop as human beings during a period of intense suffering. It can make us or break us, and sometimes seems to be doing both.
Behaving as well as we can, establishing clear boundaries, and being as kind as we can(in my case not always very kind) After all they may well not come out of the crisis ever, and even if they do, may not want to re-connect with us. We have our lives to lead regardless.
The occasional glimpses of sanity I have seen in my husband over the past few years confirm that in my case certainly, the crisis was going to play out in its own time, and is still very much on-going. Sometimes he can explain bits of it, from his perspective, and it makes no sense to me. The person that we really are is not apparent to the MLC spouse. We are, or seem to be, a symbol of all that they dislike and is making them unhappy in their eyes.
So do what you feel is right and decent, and try not to worry about the effect on the WAS. Most of us focus far too much on them, and not nearly enough on taking care of ourselves. Eventually I believe the truth of all situations emerges anyway.